“It is a little difficult for the players,” Chile coach Juan Antonio Pizzi said. “Even if it is the right decision, this has an impact on players’ emotions and feelings.”

Chile’s star player Arturo Vidal fiercely argued with referee Damir Skomina when a goal scored in first-half stoppage time by Eduardo Vargas was overruled almost one minute later. FIFA later released still images of a razor-thin margin of the offside ruling.

Video review seems to have plenty to prove to football’s rule-making panel, known as IFAB. Its decision is due in March whether to approve it for use at the World Cup, as FIFA President Gianni Infantino wants.

Four incidents on just the second day of the biggest tournament so far to conduct live trials has created more controversy than FIFA expected.

One “clear error” might be overturned every four or five games, FIFA head of refereeing Massimo Busacca suggested last year.

“If this is going to happen several times during a game, well it’s not very pleasant for the players,” Cameroon coach Hugo Broos said.

Count Vidal among the current skeptics. Chile players had done their choreographed goal celebration routine and were moving back into position for the restart when referee Skomina signaled for a review.

FIFA wants to keep fans in the loop by showing slow motion images on stadium giant screens. Vidal angrily directed the referee — relying on his three video assistant referees (VARs) to interpret images he was not watching — to check them himself.

The uncertainty lasted far beyond the six-second target FIFA had set last year for officials to review their opinions.

It took at least 30 seconds for Vargas’s goal in second-half stoppage time to be confirmed after Alexia Sanchez was judged not to have been in an offside position earlier in the move.

Against Mexico, Portugal had to wait to find out that the score would stay at 0-0 in the first half when Nani’s shot was overruled for an offside call that went unflagged in an earlier phase of play.

More confusion was caused when Argentine referee Nestor Pitana called a review for unclear reasons after defender Cedric Soares’s deflected shot in the 86th gave Portugal a 2-1 lead.

“It’s the new rule, and if it brings benefits to football, that’s fine,” Portugal coach Fernando Santos said. “But we have to be careful because I don’t think people understand this new rule really well.”